Platform Delivering a Command

Function

This API is used by the platform to deliver a command to a device. After the platform delivers a command, the device needs to return the command execution result to the platform in a timely manner. Otherwise, the platform considers that the command execution has timed out. For differences between command delivery and message delivery, see Message Communications.

It is not suitable to report data in JSON format for devices with low configuration and limited resources or with limits on bandwidth usage. In this case, devices can transparently transmit the original binary data to the platform, but a codec is required to convert binary data to JSON format. For details about how to develop codecs, see Developing a Codec.

Topic

Downstream: $oc/devices/{device_id}/sys/commands/request_id={request_id}

Upstream: $oc/devices/{device_id}/sys/commands/response/request_id={request_id}

{request_id} is used to uniquely identify a request. If a device receives a downstream request with a topic carrying a request ID, the request ID must be included in the topic of the upstream response returned by the device.
When an application delivers a device command through the platform, the platform generates a unique ID (command_id) to identify the command and returns the ID to the application. In addition, the ID is sent to the device through requst_id in the downstream topic of the device command.
The device cannot detect the request_id in advance. When a device subscribes to a topic that ends with request_id={request_id}, the number sign (#) can be used to replaced request_id={request_id}, for example, $oc/devices/{device_id}/sys/commands/#.

Downstream Request Parameters

Parameter	Mandatory or Optional	Type	Description
object_device_id	Optional	String	For gateway child device: The value is the child device ID in the topic. For directly connected device: The value is the same that of device_id in the topic.
service_id	Optional	String	Device service ID, which is defined in the product model associated with the device.
command_name	Optional	String	Device command name, which is defined in the product model associated with the device.
paras	Mandatory	Object	Command execution parameters, which are defined in the product model associated with the device.

Upstream Response Parameters

Responses are in JSON format.

Parameter	Mandatory or Optional	Type	Description
result_code	Optional	Integer	Command execution result. 0 indicates a successful execution, whereas other values indicate an execution failure. If this parameter is not specified, the default value 0 is used.
response_name	Optional	String	Response name of the command.
paras	Optional	Object	Indicates the response parameters, which are defined in the product model associated with the device.

Example Downstream Request

Topic: $oc/devices/{device_id}/sys/commands/request_id={request_id} 
Data format:
{
  "object_device_id": "{object_device_id}",
  "command_name": "ON_OFF",
  "service_id": "WaterMeter",
  "paras": {
    "value": "1"
  }
}

Example Upstream Response

Topic: $oc/devices/{device_id}/sys/commands/response/request_id={request_id}
Data format:
{
    "result_code": 0,
    "response_name": "COMMAND_RESPONSE",
    "paras": {
        "result": "success"
    }
}

Parent topic: Device Commands

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